Project Description

A full project description can be found on Find a PhD. Please see below for additional information about this project:

Sediment core logging and sampling to be completed on site in core repositories (national and international) where possible. Samples will be analysed for: (1) composition (using XRF and smear slide microscope analysis); (2) textural characteristics (sediment grainsize distribution using laser particle analyser, analysed in software GRADISTAT); (3) sediment microplastic fraction and composition using settling methods and microscope analysis; and (4) benthic foraminifera assemblages through microscope analysis. 14C dating of a subset of samples will be competed externally (SUERC). Multivariant data analysis to be completed in R (training to be provided). Bathymetric mapping and synthesis of results completed in ArcGIS.

Additional training in marine geoscience will be supported including attendance of the IODP (international Ocean Discovery Program) summer school scheme, BSRG (British Sedimentological Research Group) postgraduate workshops and possible shipboard time to collect samples. Early opportunity to attend the 4th Deep Water Circulation Meeting (Edinburgh) and associated fieldtrip (Cyprus).

Essential skills

  • The PhD candidate should have a good grounding in geological or marine science.
  • Strong numeracy and analytical skills are essential for statistical analysis of textural, biological and microplastic particle results.
  • An ability to work unsupervised with a strong attention to detail is essential.
  • The candidate must be willing to travel for data collection.

Desired skills

  • Previous experience in lab techniques, or a proven ability to learn is desirable, however training in analytical sedimentology and microbiology lab techniques will be provided.
  • Experience in R software and language, and ArcGIS is desirable, but not essential.
  • The candidate should be willing to disseminate research results thorough conferences and academic publications. As such, strong communication skills are desirable.

Photo by Klaus Beyer from Pixabay

Supervisors

Rachel Brackenridge

Primary Supervisor:

Profile: Rachel Brackenridge
Email: rachel.brackenridge@abdn.ac.uk
Institution: University of Aberdeen
Department/School: School of Geosciences

Patrick Collins

Secondary Supervisor:

Profile: Patrick Collins
Email: Patrick.Collins@qub.ac.uk
Institution: Queen's University, Belfast
Department/School: School of Biological Sciences

Adrian Hartley

Additional Supervisor:

Profile: Adrian Hartley
Email: a.hartley@abdn.ac.uk
Institution: University of Aberdeen
Department/School: School of Geosciences

References

Kane, I.A., Clare, M.A., Miramontes, E., Wogelius, R., Rothwell, J.J., Garreau, P. and Pohl, F., 2020. Seafloor microplastic hotspots controlled by deep-sea circulation. Science, 368(6495), pp.1140-114

Koelmans, A.A., Kooi, M., Law, K.L. and Van Sebille, E., 2017. All is not lost: deriving a top-down mass budget of plastic at sea. Environmental Research Letters, 12(11), p.1140

Rebesco, M., Hernández-Molina, F.J., Van Rooij, D. and Wåhlin, A., 2014. Contourites and associated sediments controlled by deep-water circulation processes: State-of-the-art and future considerations. Marine Geology, 352, pp.111-154.

Impact

This research aims to answer the outstanding question of where plastics entering the ocean ultimately accumulate, and if they pose a negative influence on the benthic organisms living within the sediments. By understanding this, we hope to (1) predict the location of microplastic accumulation hot spots around the ocean basins using oceanographic data; (2) assess if different types of microplastic particle types are altering benthic assemblages or activities; and (3) identify regions and/or plastic types that are should be prioritised for policy change to stem the influx of waste into the ocean basins.

Research into plastic waste has been ongoing for several decades. However, much of the past research has been strongly focused on marine biology aspects of plastic sequestration. This is driven by concerns that that chemicals introduced during manufacturing or consumption of plastics are rife in the food chain with potential adverse consequences for environmental health and human food security. Much data has been gathered from sea surface and nearshore studies on plastic distribution, with ocean surface current modelling and monitoring giving insight to the distribution of floating waste. Much less is known about the influx of waste into the deep ocean basins. Limited studies show that canyon systems across the continental slopes are efficient at transporting micro and macro plastic material into the deep basin, where deep ocean currents have the potential to redistribute plastics across the continental slopes, rise and abyssal plains. This interaction with ocean currents remains a gap in understanding, and will complete the source-to-sink story for plastics in the environment.

This multidisciplinary study is unique in combining geological, oceanographic and marine biology understanding to address these outstanding research questions, with broad appeal to scientists, industry and policy makers working across multiple streams of microplastic research.

Proposed Timetable

Year 1
Data acquisition and literature review form the main aims of this first year of the project. Detailed sediment core logging and subsequent high-resolution sampling of the near seabed to be completed at various core repositories through the year. The candidate will be encouraged to attend the 4th Deep Water Circulation conference (held in Edinburgh late 2022) and the BSRG Annual General meeting (Dec 2022) to build their network and meet project partners. Early training through an application to the IODP Summer School 2023 will be strongly advised.

Year 2
Continued sediment sampling and core logging at core repository sites. Year two will focus on data acquisition in the laboratory. Sediment will be characterised in the laboratory (using microscope, XRF and grain size analysis) to define the present day depositional environments across the study area. This will include compositional, textural and ecological analyses. Results will be integrated with bathymetric mapping to understand the present day gross depositional environments across the study area. Target research cruise participation either year 2 or year 3.

Year 3
Remaining laboratory analysis and microplastic and benthic foraminifera extraction and analysis. Full multivariant statistical analyses to be completed with the aim to identify the controls on microplastic distribution across contourite depositional systems and associated bottom current energy regimes. Investigation and publication on the results of controls on benthic assemblages and activity.

Year 4
Completion of multivariant analyses, final write up and publication of thesis results.

QUADRAT Themes

  • biodiversity
  • earth-systems
  • environmental-management

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